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The Science Seminar Series: OCtober 7, 2010
Phylogeny, Biogeography, & Morphological Evolution of the Gaultherieae
Dr. Catherine Bush
Department of Biology
Valdosta State University
Student Union Theater
Time: 4:00 -5:00pm
The plant tribe Gaultherieae (Ericaceae: subfamily Vaccinioideae) comprises seven genera with a total of approximately 250 species. The group exhibits an amphi-Pacific distribution, that is, temperate and tropical regions of the Americas, eastern Asia, Southeast Asia, and New Guinea, Australia, and New Zealand. Phylogenetic analyses using DNA sequence data have shown that the Gaultherieae and the wintergreen group are monophyletic. Several strongly supported clades within the wintergreen group (i.e., Gaultheria s.s.) include members from a particular geographic region. Phylogenetic relationships within Gaultheria L. from Australia and New Zealand were examined by using DNA sequence data and it was found that all Australia/New Zealand species form a clade that is sister to a clade of temperate South American species. The disjunct Brazilian species of Gaultheria were also analyzed in a molecular phylogeny. Six species of Gaultheria are endemic to the Mata Atlantica (Atlantic rainforest) in Brazil, several of which exhibit unique morphological characters within Gaultheria. A strongly supported clade of five Brazilian endemics was recovered (corresponding to the currently recognized G. ser. Myrtilloideae clade) and is sister to a clade of Gaultheria from temperate South America. Gaultheria serrata, another endemic Gaultheria species and two other Gaultheria that exhibit distributions in Brazil and the Andes are closely related to each other and other species from the Andes/Mexico. These results support the hypothesis that some Brazilian species of Gaultheria are derived from Andean ancestors. However, the G. ser. Myrtilloideae clade is imbedded within a clade containing species from temperate South America, indicating that the Andes may not have served as the only source area for the species in the Mata Atlantica of Brazil.